During drilling operations, for example, drilling carried out for petroleum exploration and exploitation, it is common to handle various tubulars used or installed in a wellbore with the aid of a drilling plant. The drilling plant is commonly arranged at ground level directly above the well or, in the case of offshore wells, on a platform or a floating vessel, such as a semi-submersible rig or a drillship. Such tubulars may include drill pipe, well casing, or other types of tubular pipe used in operations relating to creating or preparing the borehole. The drilling plant commonly comprises a dedicated hoisting system for this purpose, usually having a travelling assembly which carries the tubular string and raises or lowers the string into or out of the well. Such hoisting systems may, for example, be winch-based systems (e.g., using so-called drawworks) with a multiple stringed block, such as is described in WO 2013/076207 A2 and in WO 2014/209131 A1. An alternative solution is a cylinder lifting rig, such as the RamRig™ technology supplied by the current applicant. An example of a possible arrangement is described in WO 97/23705 A1.
Safe and reliable operation is of utmost importance when handling such tubular pipe extending into the wellbore in drilling plants. Irregularities in the pipe handling may, for example, compromise health and safety on the drill floor. Significant extra costs may also be incurred, both due to direct damage and delays, in the case of damage to the pipe, associated equipment, and/or to the well.